constant velocity joint

Abstract

The constant velocity joint includes: an outer race; an inner race disposed within the outer race; a plurality of balls disposed between the outer and inner races and serving as a medium for transmitting rotational power between the outer and inner races; a ball cage housing the plurality of balls; a protective adapter disposed on one side of the outer race; and a ball retainer disposed on the other side of the outer race. The outer race and the protective adapter, as well as the outer race and the ball retainer, are joined together by contact surfaces having a sealant layer formed thereon; and the sealant layer is formed by pressing a pre-sealed sealant pattern applied to the contact surfaces. The ten-point average roughness (Rz) of the contact surfaces is in the range of 10 μm to 50 μm.

Description

Technical Field

[0001] This disclosure relates to a constant velocity joint for transmitting driving power of a vehicle. Background Technology

[0002] A constant velocity joint, as a power transmission component, is a part of the drive system that transmits the driving power generated by a vehicle's power source (e.g., an internal combustion engine or an electric motor) to the wheels. It is well known that a constant velocity joint is configured to transmit the rotational power generated by the vehicle's power source at a constant speed.

[0003] Typically, ball-type constant velocity joints are configured such that rotational power is transmitted between the outer and inner races via balls housed in a window within a ball cage, simultaneously positioned between the outer and inner races. The balls are disposed in a space formed by an outer ball groove formed on the inner circumferential surface of the outer race and a corresponding inner ball groove formed on the outer circumferential surface of the inner race, serving as the medium for transmitting rotational power between the outer and inner races. In this regard, the outer and inner ball grooves for accommodating the balls can be implemented in various forms; as an example, a constant velocity joint having outer and inner ball grooves formed to intersect each other relative to the longitudinal direction of the joint has been introduced. This type of constant velocity joint is called a cross-groove type constant velocity joint.

[0004] In certain types of cross-groove constant velocity joints, a ball retainer and a protective adapter for accommodating the balls are coupled to opposite ends of the outer race in its longitudinal direction. A sealant is applied to the contact surfaces between the outer race and the ball retainer, and between the outer race and the protective adapter, to improve adhesion. The characteristics of the sealant layer are affected by the surface roughness of the contact surfaces of the outer race, the pressure applied during engagement, the pressing area, and the sealant area. Optimizing these conditions is necessary to achieve optimal sealing characteristics through the sealant layer.

[0005] The matters described in the section relating to the background art of the invention are provided to enhance the understanding of the background art of the invention, and may include matters that do not constitute prior art already known in the field to which the invention pertains. Summary of the Invention

[0006] [Technical Issues]

[0007] The purpose of this invention is to provide a constant velocity joint that improves the sealing characteristics between the outer race and the protective adapter, as well as between the outer race and the ball retainer.

[0008] The technical problems to be solved by the present invention are not limited to those described above, and those skilled in the art will understand from the following description other technical problems not described herein.

[0009] [Technical Solution]

[0010] The constant velocity joint according to an embodiment of the present invention includes an outer race, an inner race disposed within the outer race, a plurality of balls disposed between the outer and inner races and serving as a medium for transmitting rotational power between the outer and inner races, a ball retainer housing the plurality of balls, a protective adapter disposed on one side of the outer race, and a ball retainer disposed on the other side of the outer race. The outer race and the protective adapter, as well as the outer race and the ball retainer, are joined to each other by contact surfaces having a sealant layer formed thereon, and the sealant layer is formed by pressing a pre-applied sealant pattern applied to the contact surfaces. The ten-point average roughness (Rz) of the contact surfaces is in the range of 10 μm to 50 μm.

[0011] The pre-applied sealant pattern can be pressed by a press fixture, and the press fixture can be configured to press the pre-applied sealant pattern by applying a pressure in the range of 1.25 MPa to 2.5 MPa.

[0012] The ratio of the contact area of ​​the pre-applied sealant pattern to the pressing area of ​​the press fixture can be in the range of 10% to 40%.

[0013] The ratio of the area of ​​the sealant layer to the area of ​​the contact surface can be in the range of 50% to 100%.

[0014] The contact surface can be formed to have a ten-point average roughness (Rz) by one or more of the following processes: turning, knurling, discontinuous pitting, and continuous groove.

[0015] [Invention Effects]

[0016] According to the present invention, the sealing characteristics between the outer race and the cover adapter, and between the outer race and the ball retainer, can be improved by adjusting the surface roughness of the contact surface, the pressure of the press fixture, the ratio of the contact area of ​​the pre-applied sealant pattern to the pressing area of ​​the press fixture, and the ratio of the area of ​​the sealant layer to the area of ​​the contact surface.

[0017] Furthermore, various effects that can be obtained or anticipated from the embodiments of the present invention are disclosed directly or implicitly in the detailed description of the embodiments of the present invention. Attached Figure Description

[0018] The accompanying drawings, which are set forth below, are provided to aid in understanding the invention, and embodiments of the invention are provided together with the detailed description. However, the technical features of the invention are not limited to the specific drawings, and the features disclosed in the various drawings can be combined with each other to constitute new embodiments. Embodiments of this specification can be better understood by referring to the following description taken in conjunction with the accompanying drawings, wherein like reference numerals denote like or functionally similar elements.

[0019] Figure 1 This is a perspective view of a drive shaft including a constant velocity joint according to an embodiment of the present invention.

[0020] Figure 2 This is a partial cross-sectional view of an equal velocity joint according to an embodiment of the present invention.

[0021] Figure 3 This is a front view of an equal velocity joint according to an embodiment of the present invention, wherein the guard, guard adapter and ball retainer have been removed.

[0022] Figure 4 This is a view showing the outer and inner ball grooves of the constant velocity joint according to an embodiment of the present invention projected onto a plane.

[0023] Figure 5 This shows the power transmission shaft and the protective cover from Figure 1 A 3D view of the state of the constant velocity connector after removal.

[0024] Figure 6 It is along Figure 5 The cross-sectional view taken from line AA.

[0025] Figure 7 This is an exploded perspective view of the outer and inner races of the constant velocity joint according to an embodiment of the present invention.

[0026] Figure 8 This is an exploded perspective view of the ball cage and balls of the constant velocity joint according to an embodiment of the present invention.

[0027] Figure 9 (a) illustrates the shape of a pre-applied sealant pattern formed on the contact surface of a shield adapter of a constant velocity joint according to an embodiment of the invention. Figure 9 (b) shows the shape of the sealant layer formed by pressing.

[0028] Figure 10 (a) shows a pattern of pre-applied sealant formed on the contact surface of the ball retainer of a constant velocity joint according to an embodiment of the invention. Figure 10 (b) shows the shape of the sealant layer formed by pressing.

[0029] Figure 11This is a view used to explain the process of pressing an applied sealant pattern using a press fixture in an embodiment of the invention.

[0030] The accompanying drawings mentioned above are not necessarily drawn to scale and should be understood as simplified representations of various features illustrating the basic principles of the invention. For example, specific design features of the invention (including particular dimensions, orientations, positions, and shapes) will be determined in part by the specific intended application and environment of use. Detailed Implementation

[0031] In the following, embodiments of the invention will be described in detail with reference to the accompanying drawings, enabling those skilled in the art to readily practice the invention. However, this disclosure may be implemented in various different forms and is not limited to the exemplary embodiments described herein.

[0032] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein, the singular form is also intended to include the plural form unless the context clearly indicates otherwise. It should also be understood that, when used in this specification, the terms “comprising” and / or “including” specify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, components, and / or groups thereof. As used herein, the term “and / or” includes any one and all combinations of one or more associated listed items. As used herein, the term “coupled” indicates a physical relationship between two components, wherein the components are directly connected to each other or indirectly connected through one or more intermediate components.

[0033] In describing the constituent elements of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are used only for the purpose of distinguishing one constituent element from another and do not limit the nature, order, or sequence of the corresponding constituent elements. When a constituent element is described as being “connected,” “coupled,” or “joined” to another constituent element, it should be understood that a constituent element may be directly connected, coupled, or joined to another constituent element, but it may also be “connected,” “coupled,” or “joined” between them.

[0034] Figure 1 This is a perspective view of an equal velocity joint according to an embodiment of the present invention. Figure 2 This is a partial cross-sectional view of a so-called cross-groove type constant velocity joint according to an embodiment of the present invention. Figure 3 This shows the power transmission shaft, guard, guard adapter, and ball retainer. Figure 1 A 3D view of the state after the constant velocity joint has been removed. Figure 4This is a view showing the outer and inner ball grooves of the constant velocity joint according to an embodiment of the present invention projected onto a plane. (Reference) Figure 1 and Figure 2 According to an embodiment of the present invention, the constant velocity joint 10 can be connected to the power transmission shaft 101. The constant velocity joint 10 can be fastened to one end of the power transmission shaft 101, and the constant velocity joint 103 can be fastened to the other end of the power transmission shaft 101.

[0035] The constant velocity joint 10 can be a ball-type constant velocity joint that transmits rotational power via balls. The constant velocity joint 10 includes an outer race 11 and an inner race 21. The outer race 11 has a shape extending through in the longitudinal direction and includes a first outer ball groove 13 and a second outer ball groove 14 formed on its inner circumferential surface. The inner race 21 is disposed within the interior space of the outer race 11 and includes a first inner ball groove 23 and a second inner ball groove 24 formed on its outer circumferential surface. The first outer ball groove 13 and the first inner ball groove 23 form a pair, and balls 31 are disposed in the space formed by the pair of the first outer ball groove 13 and the first inner ball groove 23. Additionally, the second outer ball groove 14 and the second inner ball groove 24 form a pair, and balls 31 are disposed in the space formed by the pair of the second outer ball groove 14 and the second inner ball groove 24. The balls 31 can be arranged circumferentially, and each ball 31 can be disposed in a window 35 of a ball cage 33. The ball bearings 31 can be arranged in the circumferential direction.

[0036] refer to Figure 3 and Figure 4 The first outer ball groove 13 and the second outer ball groove 14 are inclined in opposite directions relative to the longitudinal direction, and are arranged alternately along the circumferential direction. Similarly, the first inner ball groove 23 and the second inner ball groove 24 are also inclined in opposite directions relative to the longitudinal direction, and are arranged alternately along the circumferential direction. In this case, the paired first outer ball groove 13 and the first inner ball groove 23 are inclined in opposite directions relative to the longitudinal direction, and the paired second outer ball groove 14 and the second inner ball groove 24 are inclined in opposite directions relative to the longitudinal direction. A constant velocity joint having this type of ball groove is called a cross-groove type constant velocity joint.

[0037] Figure 5 This shows the power transmission shaft and the protective cover from Figure 1 A 3D view of the state after the constant velocity joint has been removed. Figure 6 yes Figure 5 A rear-view perspective view of the constant velocity joint. (Reference) Figure 5 and Figure 6The cover adapter 41 is fastened to one side of the outer race 11, and the ball retainer 51 is fastened to the other side of the outer race 11. The outer race 11 includes a first contact surface 11a and a second contact surface 11b located on opposite sides in the longitudinal direction, and the cover adapter 41 and the ball retainer 51 are fastened to the outer race 11, contacting the first contact surface 11a and the second contact surface 11b, respectively. The outer race 11 includes a plurality of fastening holes 11c extending parallel to the longitudinal direction, and the cover adapter 41 and the ball retainer 51 also include fastening holes 42 and 52 formed at corresponding locations, respectively. By inserting and securing a fastening device such as a fastening rod into the fastening holes 42, 11c, and 52, the cover adapter 41, the outer race 11, and the ball retainer 51 can be secured to the vehicle's transmission.

[0038] The shield adapter 41 includes a shield mounting portion 43 to which the shield 61 is fastened. The shield mounting portion 43 may have a substantially hollow cylindrical shape extending along the longitudinal direction of the constant velocity joint 10. Figure 1 and Figure 2 As shown, one end of the cover 61 is fixed to the cover mounting portion 43, and the other end is fixed to the power transmission shaft 101. Additionally, the cover adapter 41 includes a ball gap portion 45 extending radially outward from one end of the cover mounting portion 43. The ball gap portion 45 forms a contact surface 46 that contacts the first contact surface 11a of the outer race 11. The ball gap portion 45 provides clearance space when the balls 31 move longitudinally within the outer and inner ball grooves of the outer race 11 and the inner race 21. The aforementioned fastening hole 42 can be formed in the ball gap portion 45.

[0039] The ball retainer 51 includes a retaining portion 53 for fixing the ball 31 to move in the longitudinal direction and preventing the ball 31 from separating, and a ball gap portion 55 extending radially outward from one end of the retaining portion 53. The ball gap portion 55 forms a contact surface 56 that contacts the second contact surface 11b of the outer race 11. The aforementioned fastening hole 52 may be formed in the contact surface 56.

[0040] In an embodiment of the invention, a sealant is applied to the contact surface 46 of the cover adapter 41 and the contact surface 56 of the ball retainer 51, thereby providing sufficient sealing properties for the grease seal between the outer race 11 and the cover adapter 41 and between the outer race 11 and the ball retainer 51.

[0041] First, in embodiments of the present invention, the ten-point average roughness (Rz) value of the surface on which the sealant is applied can be in the range of 10 μm to 50 μm. In this case, the surface on which the sealant is applied can be the contact surface 46 of the shield adapter 41, the contact surface 56 of the ball retainer 51, or the contact surfaces 11a and 11b of the outer race 11. Figure 9 (a) shows the shape of a pre-applied sealant pattern 71 formed on the contact surface 46 of the shield adapter 41 of the constant velocity joint. Figure 9 (b) shows the shape of the sealant layer 73 obtained by the shape change of the sealant pattern 71 caused by pressing with a clamp. Furthermore, Figure 10 (a) shows a pre-applied sealant pattern 81 formed on the contact surface 56 of the ball retainer 51 of the constant velocity joint. Figure 10 (b) shows the shape of the sealant layer 83 obtained by the shape change of the sealant pattern 81 caused by pressing with a clamp.

[0042] As a result of actual testing, it was confirmed that no grease leakage occurred when the surface roughness (Rz) of the contact surface with the sealant layer was in the range of 11 μm to 25 μm. Furthermore, air leakage tests were conducted by applying air pressures of 0.5, 1.0, and 1.5 bar when samples with a surface roughness (Rz) of 11 μm to 25 μm were immersed in water. The results confirmed excellent sealing performance, ensuring that no air bubbles were generated even when an air pressure of 1.5 bar was applied and the shield was in an expanded state.

[0043] To ensure the aforementioned surface roughness, turning, knurling, discontinuous pitting, and continuous groove processing can be used to treat the surface to which the sealant is applied.

[0044] Figure 11 This is a view illustrating the process of applying a pre-applied sealant pattern 71 or 81 by pressing it with a press clamp 91. The pressing pressure of the press clamp 91 can be in the range of 1.25 MPa to 2.5 MPa. Furthermore, the ratio of the contact area of ​​the pre-applied sealant pattern 71, 81 to the pressing area of ​​the press clamp 91 can be in the range of 10% to 40%.

[0045] In addition, the ratio of the area of ​​sealant layers 73 and 83 to the area of ​​contact surfaces 46 and 56 can be in the range of 50% to 100%.

[0046] Although embodiments of the invention have been described above, the scope of the invention is not limited thereto, and includes all changes and modifications that can be readily made by those skilled in the art from the embodiments of the invention and are considered equivalents.

Claims

1. A constant velocity coupling, comprising: Outer seat ring; An inner race is disposed within the outer race; Multiple balls are disposed between the outer race and the inner race and serve as a medium for transmitting rotational power between the outer race and the inner race; A ball cage that houses the plurality of balls; A protective adapter is disposed on one side of the outer seat ring; as well as A ball retainer is located on the other side of the outer race. The outer race and the protective adapter, as well as the outer race and the ball retainer, are joined together by contact surfaces with sealant layers formed on them. The sealant layer is formed by pressing a pre-applied sealant pattern onto the contact surface, and The ten-point average roughness (Rz) of the contact surface is in the range of 10 μm to 50 μm.

2. The constant velocity connector according to claim 1, The pre-applied sealant pattern is pressed by a press fixture, and The press fixture is configured to press the pre-applied sealant pattern by applying a pressure in the range of 1.25 MPa to 2.5 MPa.

3. The constant velocity joint according to claim 2, The ratio of the contact area of ​​the pre-applied sealant pattern to the pressing area of ​​the press fixture is in the range of 10% to 40%.

4. The constant velocity joint according to claim 3, The ratio of the area of ​​the sealant layer to the area of ​​the contact surface is in the range of 50% to 100%.

5. The constant velocity connector according to claim 1, The contact surface is formed to have the ten-point average roughness (Rz) by one or more of turning, knurling, discontinuous pitting, and continuous groove machining.

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